1. Field of the Invention
The present invention relates to steam distillation and liquid separation processes, and in particular relates to an apparatus for separating water from both lighter and heavier immiscible solvents.
2. Description of the Prior Art
A steam distillation apparatus for recycling various solvents which are immiscible in water are well known. Devices for separating water from the distilled solvent are also well known. One such separation device is disclosed in U.S. Pat. No. 3,692,467, issued to Durr et al. on Sept. 19, 1972. While such devices perform admirably for the solvent for which they were designed, they are not appropriate for use with both solvents which are heavier than water and solvents which are lighter than water. Since the materials used in manufacturing such devices are typically high quality stainless steel, the cost of a separate water separator for a second type of solvent is quite high.
Other solvent separating or recovery systems are also known in the prior art. In U.S. Pat. No. 3,666,633, issued to Essex et al. on May 30, 1972, there is disclosed an apparatus for recovering organic solvents immiscible with water. Similar apparatus are also disclosed in U.S. Pat. Nos. 3,853,513, issued to Carson on Dec. 10, 1974, and 3,334,025, issued to Reid on Aug. 1, 1967. As is typical of most of the prior art devices, however, the devices disclosed in the above patents are not useful in separating solvents which are heavier than water as well as solvents which are lighter than water from the distillate water.
A device intended for separating both the heavier and lighter immiscible solvents from water is disclosed in U.S. Pat. No. 4,036,701, issued to Clay et al. on July 19, 1977. As disclosed in that reference, the distillation apparatus and associated separation means comprised an apparatus which was convertible to accommodate the solvents that were heavier or lighter than the water. In particular, a pair of outlet openings from the first tank were designed and located such that the attachment of a tube extending selectively from one or the other to the bottom of the tank would permit the apparatus to operate to separate water from either a lighter solvent or a heavier solvent. The Clay et al. device represents a significant improvement over some of the prior art devices in the fact that a device was provided which was readily convertible for use with either lighter or heavier than water solvents. The present invention provides a further improved apparatus which does not require a conversion but it directly usable with a mixture of water and both heavier and lighter than water solvents.